Recent content by Elissa89

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    MHB Is Tan(cos2x) equal to tan(2 cos^-1(x))?

    I'm not sure I understand
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    MHB Is Tan(cos2x) equal to tan(2 cos^-1(x))?

    tan(2 cos^-1(x)) I'm pretty sure 2 cos^-1(x) is the same as cos2x, the doubles formula, but from there I'm completely lost.
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    MHB Graph the function y=-1/2[cos(x+pi)+cos(x-pi)] and make a conjecture

    I don't even know what a conjecture is y=-1/2[cos(x+pi)+cos(x-pi)]
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    MHB Express in terms of sine function of f(x)=sinx+cosx

    f(x)=sinx+cosx getting really frustrated with my math teacher. gives us forumlas for things but then barely shows us how to use them if at all and then throws problems at that we have to make sense of ourself. why can't math teachers teach? anyway, the question is express f(x)=sinx+cosx in...
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    MHB Proving Addition/Subtraction Formulas - Tan(x-y)+Tan(y-z)+Tan(z-x)

    tan(x-y)+tan(y-z)+tan(z-x)=tan(x-y)tan(y-z)tan(z-x) I have redone this problem two or three times and all the steps just make my head spin. I've tried looking up tutorials online but they introduce things into the problem that we haven't been taught yet and that just confuses me more. Help!
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    MHB Find the square roots of 4*sqrt(3)+4(i)

    No, i don't know what the right side means. - - - Updated - - - Actually I don' know what any of that means. Where did the 8 come from?
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    MHB Find the distance between points C and D if the height of the tree is 4m

    So the question is...From point C on the ground level, the angle of elevation to the top of a tree is 30 degrees. From point D, which is closer to the tree, the angle of elevation is measured to be 45 degrees. Find the distance between points C and D if the height of the tree is 4m. I know...
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    MHB Find the angle between 2 vectors w=i+3j, vector v=<5, 2>

    I know how to find the cos(theta) between two vectors but I do not know how to find the sin(theta). vector w=i+3j vector v=<5, 2>
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    MHB Find the square roots of 4*sqrt(3)+4(i)

    So I have a study guide for my final which was written by a different professor from my actual professor. So I don't understand the question, I don't know if it's because my professor did not teach this or if the wording is different from what I'm used to: Find the square roots of 4*sqrt(3)+4(i)
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    MHB Express cos(2 tan^-1(x/4)) and sin(2tan^-1(x/4) as an algebraic expression in x

    but its 2*tan^-1(x/4). Isn't that the same as 2*tan(theta)=x/4. So wouldn't I divide both sides by 2 and get x/8 and go from there?
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    MHB What is the area of an isosceles triangle with side lengths 6, 6, and 4?

    Side lengths are a=6, b=6, c=4. Find the area A=1/2*b*h I split the triangle in half to find the height. Since the base is 4, that divided the base into 2: 2^2+h^2=6^2 4+h^2=36 h^2=32 h=4*sqrt(2) =========== 1/2*4*4*sqrt(2)=area of 8*sqrt(2) Did I do this correctly? I do not have an...
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    MHB Triangle ABC has area 25*sqrt(3). if Angle BAC=30 degrees, find |AC|=|BC|=?

    Triangle ABC has area 25*sqrt(3). if Angle BAC=30 degrees, find |AC|=|BC|=? the answer I got was 10*4th root(3) Is this correct? I am asking because someone other than my professor wrote the study guid for us for the final and I am not 100% sure what |AC|=|BC| means as my professor never...
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    MHB Express cos(2 tan^-1(x/4)) and sin(2tan^-1(x/4) as an algebraic expression in x

    So my professor gave us a study guide for the final but no there is no answer key. Could someone check my answers please? Express cos(2 tan^-1(x/4)) and sin(2tan^-1(x/4) as an algebraic expression in x I got: cos(theta)=8*sqrt(x^2+64)/x^2+64 sin(theta)=x*sqrt(x^2+64)/x^2+64
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    MHB Evaluate cos 2(theta) and sin 2(theta)

    Thank you! Looks like I had the right idea.
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    MHB Evaluate cos 2(theta) and sin 2(theta)

    So my math professor gave us a study guide for the final but he's not aloud to give us the answers so I have no idea if my answers are correct or not. So if a few people could let me know what they got after trying this that would be great. If tan(theta) = -2[sqrt(2)], and theta is between 270...